package com.msh.platform.elm.common.util;

import java.io.UnsupportedEncodingException;
import java.security.MessageDigest;
import java.security.NoSuchAlgorithmException;

public class MD5Utils {  
	  
    private static final String MD5_SUFFIX = "_abcdefghijklmnopqrstuvwxyz";  
      
    /** 
     * 字符加密 
     * @param str 明文 
     * @return 返回加了后缀的加密字符 
     */  
    public static String encryptByMD5(String str) {  
        try {  
            if (str == null || str.length() < 1 || "0".equals(str))  
                str = "0";  
            String tmp = md5(str + MD5_SUFFIX, "UTF-8");  
           if (null != tmp) {  
               return replace(tmp, ":", "", -1).toLowerCase();  
           }  
        } catch (NoSuchAlgorithmException e) {  
            e.printStackTrace();  
        } catch (UnsupportedEncodingException e) {  
            e.printStackTrace();  
        }  
        return "";  
    }  
      
    /** 
     * md5加密方法，不可逆转 
     * @param str 明文 
     * @param charset 字符编码 
     * @return 
     * @throws NoSuchAlgorithmException 
     * @throws UnsupportedEncodingException 
     */  
    public static String md5(String str, String charset)   
            throws NoSuchAlgorithmException, UnsupportedEncodingException {  
        byte[] tmpInput = null;  
        if (null != str) {  
            if (null != charset) {  
                tmpInput = str.getBytes(charset);  
            } else {  
                tmpInput = str.getBytes();  
            }  
        } else {  
            return null;  
        }  
        MessageDigest alg = MessageDigest.getInstance("MD5"); // or "SHA-1"  
        alg.update(tmpInput);  
        return byte1hex(alg.digest());  
    }  
      
    /** 
     * 字节码转换成16进制字符串 
     *  
     * @param inputByte 
     * @return 
     */  
    public static String byte1hex(byte[] inputByte) {  
        if (null == inputByte) {  
            return null;  
        }  
        String resultStr = "";  
        String tmpStr = "";  
        for (int n = 0; n < inputByte.length; n++) {  
            tmpStr = (Integer.toHexString(inputByte[n] & 0XFF));  
            if (tmpStr.length() == 1)  
                resultStr = resultStr + "0" + tmpStr;  
            else  
                resultStr = resultStr + tmpStr;  
            if (n < inputByte.length - 1)  
                resultStr = resultStr + "";  
        }  
        return resultStr.toLowerCase();  
    }  
  
    public static String replace(String text, String repl, String with, int max) {  
        if (isEmpty(text) || isEmpty(repl) || with == null || max == 0) {  
            return text;  
        }  
        int start = 0;  
        int end = text.indexOf(repl, start);  
        if (end == -1) {  
            return text;  
        }  
        int replLength = repl.length();  
        int increase = with.length() - replLength;  
        increase = (increase < 0 ? 0 : increase);  
        increase *= (max < 0 ? 16 : (max > 64 ? 64 : max));  
        StringBuffer buf = new StringBuffer(text.length() + increase);  
        while (end != -1) {  
            buf.append(text.substring(start, end)).append(with);  
            start = end + replLength;  
            if (--max == 0) {  
                break;  
            }  
            end = text.indexOf(repl, start);  
        }  
        buf.append(text.substring(start));  
        return buf.toString();  
    }  
      
    public static boolean isEmpty(String str) {  
        return str == null || str.length() == 0;  
    }  
}